2.1 Field of the Technology
The present technology relates to one or more of the detection, diagnosis, treatment, prevention and amelioration of respiratory-related disorders. More specifically, the present technology relates to a component, such as a blower, or a valve for a blower, suitable for a medical device, such as a respiratory pressure therapy device.
2.2 Description of the Related Art
2.2.1 Respiratory Therapy
Continuous Positive Airway Pressure (CPAP) therapy has been used to treat Obstructive Sleep Apnea (OSA). The mechanism of action is that continuous positive airway pressure acts as a pneumatic splint and may prevent upper airway occlusion, such as by pushing the soft palate and tongue forward and away from the posterior oropharyngeal wall. Treatment of OSA by CPAP therapy may be voluntary, and hence patients may elect not to comply with therapy if they find devices used to provide such therapy one or more of: uncomfortable, difficult to use, expensive and aesthetically unappealing.
Non-invasive ventilation (NIV) provides ventilatory support to a patient through the upper airways to assist the patient breathing and/or maintain adequate oxygen levels in the body by doing some or all of the work of breathing. The ventilatory support is provided via a non-invasive patient interface. NIV has been used to treat CSR, OHS, COPD, MD and Chest Wall disorders. In some forms, the comfort and effectiveness of these therapies may be improved.
Invasive ventilation (IV) provides ventilatory support to patients that are no longer able to effectively breathe themselves and may be provided using a tracheostomy tube. In some forms, the comfort and effectiveness of these therapies may be improved.
2.2.2 Treatment Systems
These therapies may be provided by a treatment system or device.
A treatment system may comprise a Respiratory Pressure Therapy Device (RPT device), an air circuit, a humidifier, a patient interface, and data management.
2.2.2.1 Patient Interface
A patient interface may be used to interface respiratory equipment to its wearer, for example by providing a flow of air to an entrance to the airways. The flow of air may be provided via a mask to the nose and/or mouth, a tube to the mouth or a tracheostomy tube to the trachea of a patient. Depending upon the therapy to be applied, the patient interface may form a seal, e.g., with a region of the patient's face, to facilitate the delivery of gas at a pressure at sufficient variance with ambient pressure to effect therapy, e.g., at a positive pressure of about 10 cmH2O relative to ambient pressure. For other forms of therapy, such as the delivery of oxygen, the patient interface may not include a seal sufficient to facilitate delivery to the airways of a supply of gas at a positive pressure of about 10 cmH2O.
2.2.2.2 Respiratory Pressure Therapy (RPT) Device
Air pressure generators are known in a range of applications, e.g. industrial-scale ventilation systems. However, air pressure generators for medical applications have particular requirements not fulfilled by more generalised air pressure generators, such as the reliability, size and weight requirements of medical devices. In addition, even devices designed for medical treatment may suffer from shortcomings, pertaining to one or more of: comfort, noise, ease of use, efficacy, size, weight, manufacturability, cost, and reliability.
An example of the special requirements of certain RPT devices is acoustic noise.
Table of noise output levels of prior RPT devices (one specimen only,measured using test method specified in ISO 3744 in CPAP mode at 10 cmH2O).A-weighted sound Year RPT Device namepower level dB(A)(approx.)C-Series Tango ™31.92007C-Series Tango ™ with Humidifier33.12007S8 Escape ™ II30.52005S8 Escape ™ II with H4i ™ Humidifier31.12005S9 AutoSet ™26.52010S9 AutoSet ™ with H5i Humidifier28.62010
Examples of RPT devices include positive airway therapy (PAP) devices and ventilators.
One known RPT device used for treating sleep disordered breathing is the S9 Sleep Therapy System, manufactured by ResMed Limited. Another example of an RPT device is a ventilator. Ventilators such as the ResMed Stellar™ Series of Adult and Paediatric Ventilators may provide support for invasive and non-invasive non-dependent ventilation for a range of patients for treating a number of conditions such as but not limited to NMD, OHS and COPD.
The ResMed Elisée™ 150 ventilator and ResMed VS III™ ventilator may provide support for invasive and non-invasive dependent ventilation suitable for adult or paediatric patients for treating a number of conditions. These ventilators provide volumetric and barometric ventilation modes with a single or double limb circuit. RPT devices typically comprise a pressure generator, such as a motor-driven blower or a compressed gas reservoir, and are configured to supply a flow of air to the airway of a patient. In some cases, the flow of air may be supplied to the airway of the patient at positive pressure. The outlet of the RPT device is connected via an air circuit to a patient interface such as those described above.
The designer of a device may be presented with an infinite number of choices to make. Design criteria often conflict, meaning that certain design choices are far from routine or inevitable. Furthermore, the comfort and efficacy of certain aspects may be highly sensitive to small, subtle changes in one or more parameters.
2.2.2.3 Blower
As described above, a treatment system may comprise a blower to generate a flow of breathable gas (e.g. air, air with enriched oxygen or oxygen) for delivery to the patient. Some examples of prior art blowers used in an RPT device are described in U.S. Pat. Nos. 6,910,483 and 8,267,648, although other blower types such as axial or mixed flow blowers may be suitable.
Typical blowers that are used in RPT devices comprise a motor (e.g. a DC electric motor), a housing, one or more rotating parts (e.g. impellers), and one or more flow directing parts (e.g. stators). Such blowers may be axisymmetric, and may further comprise one or shafts about which the rotating parts revolve.
As a result, typical electric-motor driven rotating blowers may comprise a large number of components, leading to increased complexity, costs, and/or low reparability. Furthermore, a motor such as a DC electric motor may be expensive as it may comprise a rare earth magnet, and may be heavy.
Furthermore, not all blowers may be suitable for use as a blower for an RPT device due to unique requirements of RPT devices. For example, a blower for an RPT device is preferably quiet to not disturb the patient or a bed partner, such that the patient is more likely to comply with the therapy. The blower for an RPT device may be additionally capable of providing a flow of air to the patient in synchrony with the patient's breathing, such as by being able to accelerate and/or decelerate according to a patient's breathing patterns. Furthermore, a blower for an RPT device may comprise an elevated safety and reliability standard as it may be located adjacent to the patient, with the patient pneumatically coupled thereto, and the RPT device may be potentially a life-supporting device. Thus, blowers for an RPT device may comprise a unique field or unique requirements in at least some aspects.